Fluid fuel burner



july l?, 1934. LTHQOW FLUID FUEL BURNER l Filed June l5. 1931 glen;

Patented July 17, 1934 UNITED STATES PAT-ENT OFFICE 5 Claims.

This invention relates to fluid fuel burners, and more particularly to burners for gas stoves.

One object of this invention is to provide a generally more elcient gas burner.

Another object of the invention is to provide a burner which is cheaper'to manufacture and at the same time more efficient and durable than the burners heretofore in use.

A further object of the invention is to produce a burner which is not readily clogged by overow or pan drippings and which, should it become clogged, can be readily and easily cleaned.

Another object of the invention is to provide a burner which can be renewed or reconditioned easily and at very slight cost.

A still further object of the invention is to provide a gas burner which is more efficient at low iiame.

A still further object of the invention is to provide a gas burner which will distribute its heat more uniformly over the surface being heated.

Still another object of the invention is to provide a safer burner by reason of increasing the thermal efliciency of such burner, thereby lowering the volumetric content of noxious gases in the flue gas thereof.

A further object of the invention is to provide a burner of such design as to permit the mounting of the' drip pan closer to the burner and its associated gratings.

vA still further object of the invention is to provide a design of burner such thatfferrous metals or alloys can be utilized in a die cast process of manufacture thereof.

Still another object ofthe invention is to provide a burner which will operate more eiciently than burners now in use by consuming a smaller volume of gas in producing Va given heating effect.

. These and other objects and advantages'in my invention are more fully disclosed in the detailed description which follows, reference being had to the Aaccompanying drawing in which like reference characters refer tofsimilar parts throughout the description, and in which: y

Figi is a plan view of my improved Vburner and an associated grating.;

Fig. 2 is a sectional elevation along the line 2 2 of Fig. 1;

Fig. 3 is a bottom plan view of the burnerdisc;

Fig. 4 is a modified form of burner; and

Fig. 5 isran enlarged fragment in cross-section of the burner disc.

In Fig. l the burner properf and a portion of the usual grating 8 for the support of utensils and the like and the Venturi tube 10 connecting the burner proper through the gas cock 12 to the gas line 14 illustratesthe usual disposition of these parts as found in common types of gas stove.

A particular feature of the invention whereby the thermal eiiiciency of the burner has been decidedly increased is shown in Fig. 2 by the relative situation of the burner disc 6 and the horizontal plane of its ports '7 with respect to the top of the grating 8, particularly pointed out by the arrow 9.

While it is well known by those skilled in the art that the relative distance between the ports of a burner and the surface being heated by such burner has a decided inuence on the thermal efficiency of such devices, I have found that the thermal einciency of any burner of the type generally considered here can be controlled, and increased appreciably if the distance referredto is held between the limits of one-half and threequarters of an inch.

It is a particular feature of my invention to mount my burners with respect to their associated gratings so that the burner ports will lie within this prescribed distance, and more particularly at a distance of 5A, from the top of the grating, thereby increasing the burner eiiciency.

It will be observed that the burner proper comprises a burner disc or. fuel distributing plate 6 and a cast member 10. This cast .member is formed to provide a burner head 17, from which extends in a downward direction a supporting member 14 having at its lowerrnost extremity a slot 16 designed removably to engage and rest upon a supporting rod 18, which extends across the stove frame transverse of, and beneath, the burners and intake piping.

In the horizontal type of burner shown in Fig. 2, the combination gas and air intake and mixing tube, which is preferably in the form of a Venturi tube, is provided by the horizontal extension 10 designed suitably to engage the gas cock 12 on the supply line 14. V"Ihis combination burner head and Venturi tube may be a simple mold casting which can be very inexpensively produced. 'The burner disc 6 is preferably die cast'from a metal of relatively high melting point as a ferrous metal or alloy',for example, chrome steel, Athe die casting assuring the faithful reproduction of the dimensions of the serrations or ports '7, which is an important consideration in determining the uniform eiciency of this burner, and a method not heretofore available in the manufacture of perforate gas burners.

Furthermore, in using castmetal, neither machined nor abraded, corrosion and carbon deposit :are avoided or materially decreased. i

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llli) LTA In the form of my invention shown in Fig. 2, the Venturi tube 10 extends into the burner head 17 and opens into a frusto-conical diffusing chamber 20, from which the gas issues through the ports or serrations '7 around the double faced beveled edge of the burner disc 6 at an angle of 40 to the plane of the disc. Mounting pins or prolongations 22 extend from the burner disc 6 into depressions 23 in the burner head 17. A fragment `of the usual drip pan 24 is shown to be mounted above the gas duct or Venturi tube 10 at a suitable distance below the grating 8, which prevents drippings from falling upon the gas intake piping and other parts of the stove immediately below the grating, as contrasted to the usual practice of mounting the drip pan below the burner and supply line. This feature obviates the necessity of having to clean any major portion of the burner head or its associ,- ated piping and generally provides for maintaining the stove in a cleaner condition. To clean the burner disc 6, it is merely necessary to lift it from the burner by the knob 26 and pass a brush over the serrations.

It has been found that sufficient secondary air for combustion can be supplied around the edge of the burner if the gas issues from its ports at a definite angle with respect to the surface being heated which, in this case, lies in a horizontal plane, and it has been determined that this angle should be a tolerable from the vertical center line of the burner disc. This detail is shown in the enlarged sectional fragment of Fig. 5, in which the reference character l1 denotes the uppermost bevel face of the burner disc, the character 7 indicates the port or orifice through which the gas finally issues, and the character 13 indicates the lowermost face of the beveled disc edge, While the innermost wall of the .serration or channel is indicated by the number 15. It has usually been thought necessary heretofore to supply secondary air through a hole passing through the center of the burner proper. Because of the fact that ferrous metals could not be utilized previously in casting burners in which it was necessary to provide for small gas ports or ducts by reason of the imperfect manner in which these ports or ducts were reproduced when such casting was attempted, it was necessary to either drill these ports after the rough casting had been made or to make the casting from a metal better adapted for the purpose. Metals suitable for this latter purpose, however, usually have a melting point considerably below that of the more desirable refractory metals and, as a result, it was necessary to provide means in making burners from these softer metals to prevent overheating and melting of the burner proper. One Way of doing this has been to utilize the cooling and radiating effects of a large air duct passing through the center of the burner, which also provides a means for supplying secondary air for combustion. In utilizing softer metals for burner castings,`if these and similar precautions are not taken the burner may be seriously damaged due to overheating. While this method of supplying secondary air and cooling the burner assures fairly complete combustion Without danger to the burner, it has a serious disadvantage in that the heat from such a burner is concentrated in what is known as a hot spot. That is, the heat tends to be concentrated on a particular area of the surface being heated. This is undesirable, not only because it tends to weaken utensils, especially the popular aluminum types more commonly used With domestic stoves, but also because the available heat is not distributed uniformly through the contents of such utensils. This is especially objectionable in cases Where these contents are of a solid or semi-solid nature and do not readily conduct heat.

Because of the particular design of the present burner, and more particularly because of the angular ejection of the gas therefrom and the situation of the burner with respect to the gratings, and the absence of a central or secondary air duct, the heat available from this burner is quite uniformly distributed over the heated surface, and the cooking or heating speed increased thereby by twentyone per cent. Considered apart from the increased thermal efficiency of the present burner, this fact indicates another considerable improvement which my burner embraces.

In the matter of efficiency, it has been shown that the average thermal efiiciency for a number of popular burners now on the market is about thirty-two per cent as compared with forty per cent for the efiiciency of the present burner. The increase in thermal eficiency shown here is due in part to the absence of a central or secondary air duct and, in part, to the difference between the ports and the top of the grate, the remaining increase being generally accounted for in the particular relationship between the port area and the shape of the Venturi tube utilized in the particular design disclosed in this invention.

t has been further determined that the carbon monoxide content, by volume, of the flue gases from the present burner is considerably lov/er than that for other makes and designs of burner now on the market. This is the result of the complete combustion which occurs by reason of the abundant supply of secondary air made possible rst by the definite angular ejection of the fuel gas, and second by the definite location of the orifices or burner ports with respect to the heated surface. Furthermore, the margin of safety resulting from this arrangement remains constant regardless of variations of gas pressure from the supply mains. For example, should there be an excessive 'rise in main pressure, the flame from the present burner Would merely tend to spread itself over a wider area with respect to a heated surface, which it can readily do since the gas is being directed against this heated surface at a very efficient deflecting angle.

Burners having secondary air ducts, and especially those wherein such ducts are provided with gas ports to reduce the uneven distribution of heat in the immediate region of this air duct, tend to become less efficient at increased supply pressures, and combustion is relatively incomplete inthe immediate neighborhood of the secondary air duct.

Other types of burners in which the secondary air ducts have been dispensed with are generally nc safer and no more eicient than the burner which they seek to replace because the important matter of distributing the fuel gas or flame with respect to the surface being heated has not been vconsidered and provided for'as in the present invention. For this reason the present burner'is saferand generally more desirable than other burners.

In view of the Well known effect of the flame or Contact distance from the heated surface upon thermal efliciency, it can readily be understood that at low flame the ordinary burner is likely, under certain conditions, to be considerably less efficient than at high llame. The well designed burner, however, tends to be somewhat more ecient at low llame than at high flame, though it must be understood that a burner otherwise properly designed can be appreciably less eiicient at low than at high ame. In the present invention the increase in eiciency at high ame has not been achieved at the expense of efficiency at low flame. For example, tests run under the same conditions existing in determining the former eiiciency of this burner have shown a thermal eiciency of 51% with the burner cock one-half open, and a thermal efficiency of 57% with the burner cock one-quarter open, indicating conclusively a low flame efficiency thoroughly consistent with the overall efliciency claimed for this burner.

A modified form of the present burner is shown in Fig. 4.-. The principal dierence between this burner and that of Fig. 2 is in the relative size of the burner head and the bulk of material used therein, and also in the method of centering and securing the burner disc 6 by means of an extension 28 of the handle or knob 26, which engages a depression 30 at the bottom of the gas chamber 29. A notch or yoke 32 is provided in the bottom of the burner head, as in the burner of Fig. 2, removably to engage a supporting bar 18.

The design of the burner disc being such as to permit the casting of such discs from ferrous metals or alloys, and the fact that the burner head and the intake air mixing tube can be mold cast Without detracting from the overall efficiency of the burner, due to imperfect formation of ducts and the like, provides a type of burner which can be manufactured at low cost. Furthermore, the burner disc can be readily cleaned and replaced or renewed at very slight expense.

Whereas I have illustrated my invention in a horizontal type of burner, it is to be understood that it may also be embodied in a vertical burner without departing from the spirit and scope of the invention.

Having thus described my invention what I claim is new and desire to secure by Letters Patent of the United States is:

1. A burner disc for gas stoves comprising a die cast disc of ferrous metal having a double beveled edge and a series of serrations extending uniformly from one bevel face to the other around the circumference of said disc, a knobular extension protruding centrally from an uppermost face of said disc, and a plurality of supporting pins extending from a lowermost face of said disc substantially as shown.

2. A gas burner having a combination air and gas intake and mixing duct in the form of a Venturi tube which extends into a graduated frusto-conical fuel distributing chamber open at its extremity of greatest diameter, in combination with a fuel distributing plate adapted to be removably tted into said distributing chamber and close said open extremity thereof in such manner as to permit the egress of fuel therefrom only about the edge of said distributing plate, said distributing plate having a double faced beveled edge provided with a series of uniform grooves extending from one bevel face to the other angularly with respect to the Vertical center line of said plate.

3. A burner for gas stoves comprising a burner head, a gas intake line connected thereto, and a removable gas distributing disc supported by said burner head, said distributing disc comprising a double bevel edged circle of metal having a series of grooves formed about its circumference and extending from one bevel face to the other, the upper face of said disc being provided with a knobular extension to facilitate handling, and the lower face thereof being provided with an extension designed supportably to engage a slot in said burner head.

4. A gas burner for optimum name-efficiencyspacing with respect to gratings, comprising a burner head having a frusto-conical gas chamber open at one end and communicating with gas delivery means at its other end, said open end of said chamber having a beveled edge adapted to receive a gas distributing disc having an edge provided with an upper and a lower bevel face and a plurality of gas ducts opening upon both level faces and one face of said disc.

5. A gas burner comprising a burner head having a gas chamber therein open at one end and communicating at its other end with gas supply means, and a removable gas distributing member comprising a die-cast, ferrous rnetal disc having a double-faced beveled edge and gas ducts extending from one bevel face to an oppositely disposed side of the disc, said disc being insertible in said open side of said chamber and having depending engaging means to secure it therein.

JOHN LITHGrOW.v 

